From: Keir Fraser <keir@xensource.com>
Date: Thu, 4 Oct 2007 08:40:31 +0000 (+0100)
Subject: This patch ensures xen vmm has exclusive access of vt-d hw by zapping
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~14918
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=c678acb180c75c45d75e1ca7dee6e19cba55ce33;p=xen.git

This patch ensures xen vmm has exclusive access of vt-d hw by zapping
vt-d "DMAR" ACPI table signature after xen has finished using it.

Signed-off-by: Allen Kay <allen.m.kay@intel.com>
---

diff --git a/xen/arch/x86/hvm/vmx/vtd/dmar.c b/xen/arch/x86/hvm/vmx/vtd/dmar.c
index 44ca487bdb..7103994ff6 100644
--- a/xen/arch/x86/hvm/vmx/vtd/dmar.c
+++ b/xen/arch/x86/hvm/vmx/vtd/dmar.c
@@ -483,6 +483,10 @@ acpi_parse_dmar(unsigned long phys_addr, unsigned long size)
 
         entry_header = ((void *)entry_header + entry_header->length);
     }
+
+    /* Zap APCI DMAR signature to prevent dom0 using vt-d HW. */
+    dmar->header.signature[0] = '\0';
+
     return ret;
 }